knitr::opts_chunk$set(echo = TRUE, message = FALSE, warning = FALSE)

# wrangling packages
library(here) # here makes a project transportable
library(janitor) # clean_names
library(readxl) # read excel, duh!
library(data.table) # magical data frames
library(magrittr) # pipes
library(stringr) # string functions
library(forcats) # factor functions

# analysis packages
library(emmeans) # the workhorse for inference
library(nlme) # gls and some lmm
library(lme4) # linear mixed models
library(lmerTest) # linear mixed model inference
library(afex) # ANOVA linear models
library(glmmTMB) # generalized linear models
library(MASS) # negative binomial and some other functions
library(car) # model checking and ANOVA
library(DHARMa) # model checking
library(mvtnorm)

# graphing packages
library(ggsci) # color palettes
library(ggpubr) # publication quality plots
library(ggforce) # better jitter
library(cowplot) # combine plots
library(knitr) # kable tables
library(kableExtra) # kable_styling tables
library(ggdendro)
library(dendextend)
library(ggiraph)
library(GGally)

# ggplot_the_model.R packages not loaded above
library(insight)
library(lazyWeave)

# use here from the here package
here <- here::here
# use clean_names from the janitor package
clean_names <- janitor::clean_names
# use transpose from data.table
transpose <- data.table::transpose

# load functions used by this text written by me
# ggplot_the_model.R needs to be in the folder "R"
# if you didn't download this and add to your R folder in your
# project, then this line will cause an error
#source_path <- here("R", "ggplot_the_model.R")
#source(source_path)

data_folder <- "data"
image_folder <- "images"
output_folder <- "output"

functions

deg_2_rad <- function(x){
  rad <- x*pi/180
  return(rad)
}

Importer

# data_path <- here(data_folder, "ghost_grappler.txt")
# dt <- fread(data_path)
# bike_label = "Tumbleweed Stargazer 2022"
# bike_range = "b1:h21"

read_bike <- function(bike_label = "Breezer Radar X Pro 2022",
                      bike_range = "B1:I18"){
  data_file <- "bikes.xlsx"
  data_path <- here(data_folder, data_file)
  bike_wide <- read_excel(data_path,
                          sheet = bike_label,
                          range = bike_range) %>%
    data.table
  # re-read with coltype = numeric
  # col_type_list <- c("text", "text", rep("numeric", ncol(bike_wide)-2))
  # bike_wide <- read_excel(data_path,
  #                         sheet = bike_label,
  #                         range = bike_range,
  #                         col_types = col_type_list) %>%
  #   data.table
  
  
  bike_model <- substr(bike_label, 1, nchar(bike_label) - 5)
  model_year <- substr(bike_label,
                       nchar(bike_label) - 4,
                       nchar(bike_label))
  bike_wide <- bike_wide[, -2]
  bike <- data.table(
    model = bike_model,
    year = model_year,
    transpose(bike_wide,
              keep.names = "frame_size",
              make.names = 1)
  )
  keep_names <- c("model","frame_size", "seat_tube_length", "top_tube_effective_length", "head_tube_length", "seat_tube_angle", "head_tube_angle", "chainstay_length", "wheelbase", "bottom_bracket_drop", "fork_offset_rake", "stack", "reach", "standover", "stem_length", "handlebar_width", "crank_length", "wheel_size", "tire_width_spec", "tire_width_max")
  bike <- bike[, .SD, .SDcols = keep_names]

  # constructed measures
  bike[, model_size := paste(model, frame_size)]
  bike[, rear_center := sqrt(chainstay_length^2 - bottom_bracket_drop^2)] # horizontal
  bike[, front_center := wheelbase - rear_center] # horizontal
  bike[, seat_center := stack/tan(deg_2_rad(seat_tube_angle))]
  
  # ratios
  bike[, stack_reach := stack/reach]
  bike[, front_rear := front_center/rear_center]
  bike[, rear_wheelbase := rear_center/wheelbase]
  
  # decompositions
  bike[, seat_v := seat_tube_length * sin(deg_2_rad(seat_tube_angle))]
  bike[, seat_h := seat_tube_length * cos(deg_2_rad(seat_tube_angle))]
  bike[, head_v := head_tube_length * sin(deg_2_rad(head_tube_angle))]
  bike[, head_h := head_tube_length * cos(deg_2_rad(head_tube_angle))]

  # landmarks
  bike[, x1 := 0]
  bike[, y1 := 0]
  bike[, x2 := rear_center - seat_center]
  bike[, y2 := stack - bottom_bracket_drop]
  bike[, x3 := rear_center + reach]
  bike[, y3 := stack - bottom_bracket_drop]
  bike[, x4 := x3 + head_h]
  bike[, y4 := y3 - head_v]
  bike[, x5 := wheelbase]
  bike[, y5 := 0]
  bike[, x6 := stack - bottom_bracket_drop]
  bike[, y6 := -bottom_bracket_drop]
  bike[, x7 := x6 - seat_h]
  bike[, y7 := seat_v]
  
  # landmarks_named
  bike[, rear_x := x1]
  bike[, rear_y := y1]
  bike[, seat_x := x2]
  bike[, seat_y := y2]
  bike[, head_x := x3]
  bike[, head_y := y3]
  bike[, crown_x := x4]
  bike[, crown_y := y4]
  bike[, front_x := x5]
  bike[, front_y := y5]
  bike[, bottom_x := x6]
  bike[, bottom_y := y6]
  bike[, seattube_x := x7]
  bike[, seattube_y := y7]
  
  return(bike)
}

Import

data_path <- here(data_folder, "bike_list.txt")
bike_list <- fread(data_path)
geobike <- data.table(NULL)
for(i in 1:nrow(bike_list)){
  bike_i <- read_bike(bike_label = as.character(bike_list[i, "model"]),
                      bike_range = as.character(bike_list[i, "data_range"]))
  bike_i[, my_fit := ifelse(frame_size == c(bike_list[i, "my_fit"]), TRUE, FALSE)]
  geobike <- rbind(geobike, bike_i)
}

# add Breezer small to my_fit
geobike[model == "Breezer Radar X Pro" & frame_size == "48cm (S)", my_fit := TRUE]
# add Boone 54 to my_fit
geobike[model == "Trek Boone 6" & frame_size == "54 cm", my_fit := TRUE]


# add column of shape id for plots
shape_list <- c(15,17,19,0,2)
n_shapes <- length(shape_list)
n_models <- length(unique(geobike[, model]))
n_recycles <- floor(n_models/n_shapes)
left_over <- n_models - n_recycles*n_shapes
model_2_shape_map <- c(rep(shape_list, n_recycles), shape_list[1:left_over])
geobike[, shape_id := model_2_shape_map[as.integer(as.factor(model))]]

Center landmarks at bottom bracket

y_cols <- c("rear_x", "rear_y",
            "seat_x", "seat_y",
            "head_x", "head_y",
            "crown_x", "crown_y",
            "front_x", "front_y",
            "bottom_x", "bottom_y",
            "seattube_x", "seattube_y")

# center X at bottom bracket
geobike[, rear_x := rear_x - bottom_x]
geobike[, seat_x := seat_x - bottom_x]
geobike[, head_x := head_x - bottom_x]
geobike[, crown_x := crown_x - bottom_x]
geobike[, front_x := front_x - bottom_x]
geobike[, bottom_x := bottom_x - bottom_x]
geobike[, seattube_x := seattube_x - bottom_x]

Sizes

# stack + reach size
geobike[, stack_reach_size := sqrt(stack^2 + reach^2)]
geobike[, stack_reach_size := sqrt(stack * reach)]

# effective seat tube + effective top tube size
geobike[, seat_tube_effective_length :=
          sqrt((seat_x - bottom_x)^2 + (seat_y - bottom_y)^2)]
geobike[, rider_size := sqrt(seat_tube_effective_length * 
                               top_tube_effective_length)]

# upper triangle centroid size
geobike[, centroid_x := (seat_x + bottom_x + head_x)/3]
geobike[, centroid_y := (seat_y + bottom_y + head_y)/3]
geobike[, centroid_size := 
          sqrt((seat_x - centroid_x)^2 +
          (seat_y - centroid_y)^2 +
          (bottom_x - centroid_x)^2 +
          (bottom_y - centroid_y)^2 +
          (head_x - head_x)^2 +
          (head_y - head_y)^2)]

ggscatter(data = geobike,
          x = "rider_size",
          y = "centroid_size")

gghistogram(data = geobike,
            x = "rider_size")
gghistogram(data = geobike,
            x = "reach")

scale it

size <- "stack_reach_size"
geobike[, rear_xs := rear_x/get(size)]
geobike[, rear_ys := rear_y/get(size)]
geobike[, seat_xs := seat_x/get(size)]
geobike[, seat_ys := seat_y/get(size)]
geobike[, head_xs := head_x/get(size)]
geobike[, head_ys := head_y/get(size)]
geobike[, crown_xs := crown_x/get(size)]
geobike[, crown_ys := crown_y/get(size)]
geobike[, front_xs := front_x/get(size)]
geobike[, front_ys := front_y/get(size)]
geobike[, bottom_xs := bottom_x/get(size)]
geobike[, bottom_ys := bottom_y/get(size)]
geobike[, seattube_xs := seattube_x/get(size)]
geobike[, seattube_ys := seattube_y/get(size)]

Pairwise

y_cols <- c("stack_reach", "front_rear", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle")

ggpairs(geobike[, .SD, .SDcols = y_cols])

my_fit <- geobike[my_fit == TRUE,]

shape_map <- setNames(geobike$shape_id, geobike$model)

nudge_percent <- 0.01

Stack and Reach

Notes

Stack and reach are the most common quick & dirty measure of bike sizing. Any bike in top-right is relatively big for the sizing.
High stack for a given reach is upright. A low stack is aggressive.
A long effective top tube increases reach, and is one mechanism to extend the front end to decrease toe-overlap.
For handling, increased reach increases front-center, see below.

gg1 <- ggplot(data = geobike,
             aes(x = stack,
                 y = reach,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent*(max(my_fit$stack) - min(my_fit$stack))
gg2 <- ggplot(data = my_fit,
             aes(x = stack,
                 y = reach,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

Rear-center and Front-center

Notes

Rear-center and front-center here are the horizontal components. Combined, the two sum to the wheelbase.
A large combined rear and front center (top-right quad) is a long wheelbase.
A longer wheelbase generally

increases stability in loose gravel
increases stability at speed as it lowers the center of mass

Increased front-center

increases the endo-angle – the tipping point angle of going over the bars on steep downhills.
Increased endo-angle effectively shifts weight rearward on descent (halfway to endo!), which increases grip on rear tire and better balances weight across tires. But this can cause the front tire to lose grip on a climb in a seated rider.
in standing, the weight is better centered between wheels, helping to balance grip between tires.
on steep descents, the rider doesn’t need to shift weight as far rearward to cente weight.

Long rear-center increases looping angle, the tipping-point angle to go-over backwards. This effectively shifts weight forward on a climb (half-way to going over!), which weights the front-tire and increases grip. Looping angle is also increased by a steeper seat tube.
Short rear-center

is one way to increase maneuverability (quick handling), useful for position changes in road race or maneurevering in mountain biking.
makes it easier to lift front wheel over obstacles

Cyclocross and gravel race bikes tend to have short rear and front centers. The Ritchey Outback is an exception, with a long rear-center. It get tremendous reviews.
A long rear-center is often used to increase bike-packing bag space.

gg1 <- ggplot(data = geobike,
             aes(x = front_center,
                 y = rear_center,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$front_center) -
                                min(my_fit$front_center))
gg2 <- ggplot(data = my_fit,
             aes(x = front_center,
                 y = rear_center,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

Relative rear-center

gg1 <- ggplot(data = geobike,
             aes(x = reach,
                 y = rear_wheelbase,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$reach) -
                                min(my_fit$reach))
gg2 <- ggplot(data = my_fit,
             aes(x = reach,
                 y = rear_wheelbase,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

Seat Tube Angle

Notes

A steeper seat tube angle increases looping angle, the tipping-point angle to go-over backwards. As above, this shifts weight forward on a climb (half-way to going over!), which weights the front-tire and increases grip.
Seat Tube Angle is traditionally shallow (< 74) but is steepened in bikes with long reach to decrease distance to handlebars.

Seat Tube Angle v Reach

 gg1 <- ggplot(data = geobike,
             aes(x = reach,
                 y = seat_tube_angle,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$reach) -
                                min(my_fit$reach))
gg2 <- ggplot(data = my_fit,
             aes(x = reach,
                 y = seat_tube_angle,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

Seat Tube Angle v rear-wheelbase

 gg1 <- ggplot(data = geobike,
             aes(x = rear_wheelbase,
                 y = seat_tube_angle,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$rear_wheelbase) -
                                min(my_fit$rear_wheelbase))
gg2 <- ggplot(data = my_fit,
             aes(x = rear_wheelbase,
                 y = seat_tube_angle,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

Head Tube Angle, Fork Offset

Notes

Head Tube Angle, Fork Offset, and Head Tube length are frame geometry contributions to trail but also affect toe-overlap in small bikes, especially with wide tires.
Head Tube Angle is traditionally steep (> 72°) in a road bike but is slackened in MTN bikes and progressive gravel bikes to increase front-center.
HTA is also slackened in small bikes to decrease toe-overlap.

Seat Tube Angle vs. Head Tube Angle

 gg1 <- ggplot(data = geobike,
             aes(x = head_tube_angle,
                 y = seat_tube_angle,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$head_tube_angle) -
                                min(my_fit$head_tube_angle))
gg2 <- ggplot(data = my_fit,
             aes(x = head_tube_angle,
                 y = seat_tube_angle,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

HTA vs. Fork Offset

gg1 <- ggplot(data = geobike,
             aes(x = head_tube_angle,
                 y = fork_offset_rake,
                 color = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size,
                             shape = model),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

nudge_pos <- nudge_percent * (max(my_fit$head_tube_angle) -
                                min(my_fit$head_tube_angle))
gg2 <- ggplot(data = my_fit,
             aes(x = head_tube_angle,
                 y = fork_offset_rake,
                 color = model,
                 label = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  geom_text(hjust = 0, nudge_x = nudge_pos, size = 2, show.legend = FALSE)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

PCA

Coordinates minus seatpost

y_cols <- c("rear_xs",
            "seat_xs", "seat_ys",
            "head_xs", "head_ys",
            "crown_xs", "crown_ys",
            "front_xs",
            "bottom_ys")
y_cols <- c("rear_x",
            "seat_x", "seat_y",
            "head_x", "head_y",
            "crown_x", "crown_y",
            "front_x",
            "bottom_y")
X <- geobike[, .SD, .SDcols = y_cols] %>%
  as.matrix()

S <- cov(X)

geo_eigen <- eigen(S)

L <- geo_eigen$values
E <- geo_eigen$vector
PC <- X %*% E
geobike[, pc1 := PC[, 1]]
geobike[, pc2 := PC[, 2]]
geobike[, pc3 := PC[, 3]]


round(cor(geobike[, .SD, .SDcols = c("pc1", "pc2", "pc3", y_cols)])[, 1:3], 2)

##            pc1   pc2   pc3
## pc1       1.00  0.00  0.00
## pc2       0.00  1.00  0.00
## pc3       0.00  0.00  1.00
## rear_x   -0.99  0.14 -0.03
## seat_x   -0.98  0.11  0.15
## seat_y    0.99 -0.14  0.03
## head_x   -0.88 -0.45 -0.02
## head_y    0.99 -0.14  0.03
## crown_x  -0.69 -0.69 -0.20
## crown_y   0.58  0.12  0.80
## front_x  -0.46 -0.78  0.39
## bottom_y  0.25  0.34 -0.11

gg1 <- ggplot(data = geobike,
              aes(x = pc1,
                  y = pc2,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),                          show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

gg2 <- ggplot(data = geobike,
              aes(x = pc2,
                  y = pc3,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),                          show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

gg3 <- ggplot(data = geobike,
              aes(x = pc1,
                  y = pc3,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),                          show.legend = FALSE) +
  scale_shape_manual(values = shape_map)

girafe(ggobj = gg1)

girafe(ggobj = gg2)

girafe(ggobj = gg3)

Traditional ratios and angles

y_cols <- c("stack_reach", "rear_wheelbase", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle", "seat_tube_angle")
X <- geobike[, .SD, .SDcols = y_cols] %>%
  scale()

S <- cov(X)

geo_eigen <- eigen(S)

L <- geo_eigen$values
E <- geo_eigen$vector
PC <- X %*% E
geobike[, pc1 := PC[, 1]]
geobike[, pc2 := PC[, 2]]
geobike[, pc3 := PC[, 3]]


round(cor(geobike[, .SD, .SDcols = c("pc1", "pc2", "pc3", y_cols)])[, 1:3], 2)

##                       pc1   pc2   pc3
## pc1                  1.00  0.00  0.00
## pc2                  0.00  1.00  0.00
## pc3                  0.00  0.00  1.00
## stack_reach         -0.50  0.56 -0.44
## rear_wheelbase       0.45  0.05 -0.84
## bottom_bracket_drop  0.07 -0.63  0.07
## fork_offset_rake    -0.79 -0.10 -0.27
## head_tube_angle      0.76  0.44 -0.01
## seat_tube_angle      0.14 -0.79 -0.39

gg1 <- ggplot(data = geobike,
              aes(x = pc1,
                  y = pc2,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map) +
  xlab("PC1: Offset - HTA") +
  ylab("PC2: STA - StackReach + BBD")

gg2 <- ggplot(data = geobike,
              aes(x = pc2,
                  y = pc3,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map) +
  xlab("PC2: STA - Stack_Reach + BBD") +
  ylab("PC3: Rear_Wheelbase")

gg3 <- ggplot(data = geobike,
              aes(x = pc1,
                  y = pc3,
                  color = model,
                  shape = model)) +
  geom_point_interactive(aes(tooltip = model_size,
                             data_id = model_size),
                         show.legend = FALSE) +
  scale_shape_manual(values = shape_map) +
  xlab("PC1: Offset - HTA") +
  ylab("PC3: Rear_Wheelbase")

girafe(ggobj = gg1)

girafe(ggobj = gg2)

girafe(ggobj = gg3)

Tree

treed <- function(geobike_subset,
                  y_cols,
                  scale_it = TRUE,
                  center_it = TRUE
){
  dd <- dist(scale(geobike_subset[, .SD, .SDcols = y_cols],
                   center = center_it,
                   scale = scale_it),
             method = "euclidean")
  dendro <- hclust(dd, method = "ward.D2") %>%
    as.dendrogram() %>%
    place_labels(paste(geobike_subset[, model],
                       geobike_subset[, frame_size]))
  gg <- ggdendrogram(dendro)
  return(gg)
}

Coordinates with seattube and bottom bracket

y_cols <- c("rear_x",
            "seat_x", "seat_y",
            "head_x", "head_y",
            "crown_x", "crown_y",
            "front_x",
            "bottom_y",
            "seattube_x", "seattube_y")
geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- FALSE
center_it <- FALSE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Coordinates without seattube

y_cols <- c("rear_x",
            "seat_x", "seat_y",
            "head_x", "head_y",
            "crown_x", "crown_y",
            "front_x")
geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- FALSE
center_it <- FALSE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Traditional measures with seat_tube_length

y_cols <- c("stack", "reach", "front_center", "rear_center", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle", "seat_tube_angle", "seat_tube_length")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Traditional measures without seat_tube_length

Short seat tube length designed for a dropper post

y_cols <- c("stack", "reach", "front_center", "rear_center", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle", "seat_tube_angle")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Traditional measures without seat_tube_length and without fork offset

Canyon and Chamois Hager are wacky fork offsets

From left to right

Group 1: gravel race
Group 2: adventure/race tourers
Group 3: drop-bar mountain bikes and flat-bar gravel bikes

y_cols <- c("stack", "reach", "front_center", "rear_center", "bottom_bracket_drop", "head_tube_angle", "seat_tube_angle")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Ratios and angles with seat_tube_length

y_cols <- c("stack_reach", "rear_wheelbase", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle", "seat_tube_angle", "seat_tube_length")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Ratios and angles without seat_tube_length

y_cols <- c("stack_reach", "rear_wheelbase", "bottom_bracket_drop", "fork_offset_rake", "head_tube_angle", "seat_tube_angle")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Ratios and angles without seat_tube_length or fork_offset_rake

From left to right

Group 1: drop-bar mountain bikes and flat-bar gravel bikes
Group 2: adventure tourers
Group 3: race tourers
Group 4 + 5: gravel race

y_cols <- c("stack_reach", "rear_wheelbase", "bottom_bracket_drop", "head_tube_angle", "seat_tube_angle")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Ratio measures

y_cols <- c("stack_reach", "rear_wheelbase")

geobike_subset <- geobike[my_fit == TRUE,]
scale_it <- TRUE
center_it <- TRUE
gg <- treed(geobike_subset,
            y_cols,
            scale_it,
            center_it)
gg

Bike Geometry Classifier

Jeffrey A. Walker

2022-06-07

functions

Importer

Import

Center landmarks at bottom bracket

Sizes

scale it

Pairwise

Stack and Reach

Rear-center and Front-center

Relative rear-center

Seat Tube Angle

Seat Tube Angle v Reach

Seat Tube Angle v rear-wheelbase

Head Tube Angle, Fork Offset

Seat Tube Angle vs. Head Tube Angle

HTA vs. Fork Offset

PCA

Coordinates minus seatpost

Traditional ratios and angles

Tree

Coordinates with seattube and bottom bracket

Coordinates without seattube

Traditional measures with seat_tube_length

Traditional measures without seat_tube_length

Traditional measures without seat_tube_length and without fork offset

Ratios and angles with seat_tube_length

Ratios and angles without seat_tube_length

Ratios and angles without seat_tube_length or fork_offset_rake

Ratio measures